Printed circuit boards which have electronic components mounted on them are frequently coated with a protective coating (often called a conformal coating) to shield them from contaminants and to preserve their electrical properties when moisture is present. These coatings are most commonly not solderable or weldable. That is, if an electronic component must be replaced the coating must first be removed, typically with a solvent or by mechanical means, and the surrounding coating must be protected with a mask during the soldering or welding operation. If this is not done the surrounding coating will be chemically altered by the heat and may be rendered ineffective. Also, the degradation products formed may attack the printed circuit board or alter its electrical resistance and the coating may mix with the solder to produce a questionable bond. Thus, repairing such a board can be a time-consuming and delicate operation.